Conventionally, a decelerating and reversing device for marine vessels, which propels and drives the marine vessel, is equipped with various auxiliary instruments such as a generator. A PTO transmission unit for extracting motive power is provided at an upper portion of a housing or at a periphery of an output shaft of the decelerating and reversing device for marine vessels, which causes an increase in the whole size of the decelerating and reversing device for marine vessels.
Accordingly, there has been known a technology in which a hole portion in which the PTO shaft of the PTO transmission unit is attached is formed, in addition to a hole portion in which each input shaft of forward and backward propulsion transmission units is attached in the interior of the housing, thereby storing the PTO transmission unit in the housing and achieving reduction in the whole size of the decelerating and reversing device for marine vessels (for example, see Patent Literature 1).
However, in the above-mentioned technology, the PTO transmission unit is arranged in the housing where accessibility from the outside is limited, and it is necessary to disassemble the housing each time the PTO transmission unit is attached and detached, or replaced due to the maintenance or change of specifications, which fails to provide a high degree of maintainability and exchangeability in terms of the attachment and detachment of the PTO transmission unit.
In view of this, it is conceivable that the housing is constituted by a plurality of case members, and the PTO transmission unit is stored in a member detachably disposed from the outside (hereinafter, referred to as “case cover”), out of the case members, thereby improving maintainability and versatility of the PTO transmission unit.
PTL 1: Japanese Unexamined Patent Application Publication No. 1988-116995